check valves

marc

we use spring check valves-(sweat) after the pumps to stop ghost or reverse flow. on various piping jobs we are getting a chattering noise at the check valve. i was wondering if any of you have the same problem, how do you remedy this, some customers dont like the chattering. hard to blame them when that is all you can hear at the boiler. thanks for any advice. marc

Roger_5

Distance

It is probably a velocity thing or air move the check 6 to 8 inches from the circ.

marc

most checks

are located at least 8 in. from the pump, air could be a problem at start up, but with a spirovent and time air is usually a thing of the past.

doug_16

I have swing checks

after the 2 parallel 007's in the primary. They clatter ever so lightly. When I bypass the big Ergomax that is in series with the primary loop, and thus increase flow, the clatter increases significantly. Sounds like flow/velocity related.

Tony Conner_2

Probably...

...the checks are too big, and there isn't enough flow to hold them full open. This lets them flutter up and down, like a flag in the wind. In addition to the noise, this is the cause of checks wearing out long before they're time. Ever see a swing check where it's seriously worn at the shaft that holds the disk? That's from being oversized for the flow. It's literally flapped itself to death.

Check valves are like contol valves - a pretty good rule of thumb is for them to be one pipe size smaller than the correctly sized line that they're installed in.